1. Field
This disclosure relates manufacture and testing of electrical devices prior to final assembly, and has particular application to performing tests on partially assembled electrical devices such as solar modules.
2. Background
Many electric devices, appliances and sources require dielectric voltage-withstand tests to ensure that they offer adequate protection from electric shock to their operators and users. Many such tests verify isolation between the electrically energized parts of the device and its mounting structure. In many cases the test is performed after assembly, and then the components must be disassembled to correct the detected defects. It is desired to be able to perform such tests in a manner that does not require that the component be fully assembled to its mounting structure prior to testing. This provides test results before final mounting and allows correction of the defect prior to final assembly.
Existing test methods require the user to select a mounting structure, assemble it on the device, and then run the dielectric voltage-withstand test. If such a test fails, the source of the failure needs to be identified and the device and/or mounting structure re-worked or scraped.
One existing test procedure is the “dielectric voltage-withstand test” set forth by Underwriters' Laboratories (UL). In the dielectric voltage-withstand test, an electrical device under test is tested to determine if the insulation of the electrically energized parts of the electrical device and exposed surfaces is able to withstand a predetermined voltage. In one example, applied to solar modules, the “withstand” voltage is two times the system voltage plus 1000 volts without the leakage current exceeding 50 μA. In order to accomplish this, the electrical device under test is energized at a predetermined voltage (two times the system voltage+1000 volts), with a second test electrode at the exposed surface.
One of the issues with testing is the ability to achieve testing prior to final assembly. If repairs or other modifications are to be made to the device as a result of the testing, it is desired to be able to effect such repairs prior to final assembly.